Conservative Catholics have been berating Notre Dame for extending a commencement-speaking invitation to a pro-choice president. We agree that President Barack Obama shouldn't speak at Notre Dame -- but abortion has nothing to do with it. Notre Dame practices pervasive discrimination in its admissions policies. Every year the school reserves 25 percent of the seats in its entering class for children of alumni. These "legacy preferences" result in applicants being granted or denied admission based not on their merit but on their ancestry.

Notre Dame's quota for right-ancestry students -- as reported in Daniel Golden's book The Price of Admission -- offends an American egalitarian tradition dating back to the Revolution. The Founders overthrew a semi-feudal order where rank and status were inherited rather than earned. In Gordon Wood's memorable phrase, the Revolution was "a vindication of frustrated talent at the expense of birth and blood." After transcribing the self-evident truth that "all men are created equal," Thomas Jefferson wrote that this equality encompasses "particularly the denial of a preeminence by birth." He asserted that Americans are entitled to "honor and confidence from our fellow-citizens, resulting not from birth but from our actions and their sense of them."

Notre Dame denies this fundamental equality by making access to higher education -- the very gate to social and economic advancement -- depend on inherited status. While Notre Dame has favored right-ancestor applicants, wrong-ancestor applicants have faced a plunging overall admissions rate at the university, from 49 percent in 1992 to 25 percent in 2008.

Unfortunately, Notre Dame is not alone. The Ivy League schools use legacy preferences to fill 10 percent to 15 percent of each entering class with the children of alumni. And the decline in the Ivies' overall admissions rates has been even more marked than Notre Dame's. For example, since 1992 Yale has reserved about 15 percent of each class for right-ancestor students, while its overall admissions rate plummeted from 22 percent to 8.6 percent.

With right-ancestry quotas holding steady and overall admissions rates plunging, the discrimination in the nation's elite universities has intensified dramatically. In 1992 legacy applicants were accepted at Princeton at 2.8 times the rate of wrong-ancestry students; today the disparity is 4.3 to 1. At Harvard, the admissions advantage for right-ancestry over wrong-ancestry applicants climbed from 2.2 to 1 in 1992 to more than 4 to 1 today.

These schools cannot hide behind the façade that they are "private" institutions and can discriminate however they please. They purport to be open to all on an equal opportunity basis, and each of them annually receives tens of millions of dollars in federal funds. In 2008, Notre Dame received $60 million in federal research funds; $20 million more in government grants for tuition; and $265 million in charitable donations for which we taxpayers picked up the tab of about $80 million, by way of tax deductions to the donors.

These universities are subject to the Civil Rights Act of 1866, which prohibits discrimination on the basis of race or ancestry in the admissions decisions of private schools. The 1866 Act -- the first civil-rights statute in the nation's history -- overturned the infamous Dred Scott decision, which had held that U.S. citizenship was inherited from a person's ancestors. The act mandated instead that all persons born in the United States -- "the children of all parentage whatever" -- are U.S. citizens and have an equal right to enter into contracts, including contracts to attend a school, without discrimination based on ancestry or race.

While unlawfully discriminating directly on the basis of ancestry, legacy preferences also discriminate indirectly on the basis of class and race. A 2004 Century Foundation study found that only 3 percent of students in America's elite universities come from households in the bottom quartile of socioeconomic status, and only 10 percent come from the bottom half. African Americans were first admitted to Notre Dame in 1944. In 1980, they constituted only 3 percent of the student body and remain only 4 percent today. Legacy preferences inevitably duplicate, today, the effects of class stratification and overt racial discrimination generations ago.

Despite this, public universities in Florida, Washington, and Michigan continue to grant legacy preferences while refusing to give boosts to historically oppressed minorities. Legislators in Washington state have responded by introducing a bill calling on the Obama administration and Congress to cut off all federal funds to universities that give legacy preferences, asserting that they "offend the American egalitarian tradition" and impair our "commitment to social and economic mobility based on talent and merit."

Rather than attend the Notre Dame commencement, President Obama should send in his stead a team of civil-rights lawyers from the Justice Department. But if the president does attend, his speech should include a bit of history. The legislators who drafted the 1866 Civil Rights Act that outlaws ancestry discrimination also rejected the ideas of the original Know-Nothings, who sought to reserve public offices to native-born Protestants and restrict immigration from predominantly Catholic countries. Sen. Charles Sumner of Massachusetts explained that he would have no part of "attainting men for their religion and also for their birth." Yet today Notre Dame makes admission to its elite halls, for a quarter of each class, turn on the accident of birth.

President Obama's invocation of American ideals is most powerful when he fills them with substance by tracing the historical arc of our struggle to realize them -- from Independence Hall, to Seneca Falls, to Gettysburg, to Birmingham. Inherited privileges such as legacy preferences in college admissions are anachronistic echoes of an aristocratic, status-based society; they have no proper place in a nation committed to republicanism, equality, and advancement based on talent and merit. It is absurd that we have permitted them to survive into the 21st century. As the president tries to create and sustain another progressive moment, his administration should lead the fight to abolish legacy preferences in college admissions. And he should start by giving a history lesson at Notre Dame.